There's an emerging fashion debate in China. It's between older men who roll up their shirts over their bellies to cool off and younger men who find this action crude and embarrassing. They've started calling their elders bang ye or "exposing grandfathers":

"I don't know, it just feels cooler," says Hu, perched on a park bench on a sultry weekday morning, the temperatures already into the 90s, the humidity soaring. "Look, you just shake your shirt to create a breeze. I don't see anyone laughing at me."

In the sports attire section of a nearby department store, Qi Tong scoffs at such reasoning.

"It lowers Beijing's standing as an international city," the 21-year-old says. "I go without a shirt sometimes at home, but never in public. If my dad reaches for his shirt when I'm out with him, I threaten to go home. It's just too embarrassing."